A mobile data network under construction for Perth's public trains by Chinese telecommunications giant Huawei could be used to support body-worn cameras, CCTV and live tracking of personnel and assets, government documents have revealed.

The controversial company, which won the $206 million tender in a joint venture with construction firm UGL, will build 80 radio masts – similar to mobile phone towers – along Perth's passenger rail corridors.

Government responses to potential security threats posed by Chinese telco Huawei have been mixed globally.CREDIT:AP

Last year, Premier Mark McGowan told Parliament the Huawei network was "a closed system to provide communications between train drivers and their headquarters".

"That is all it is," he said.

Huawei has been banned from Australia's 5G network over security concerns, and last week the Wall Street Journal reported concerns the company could covertly access mobile networks around the world through back doors designed for use by law enforcement agencies.

In a briefing note signed by Transport Minister Rita Saffioti just weeks before Huawei was announced as the contractor, the Public Transport Authority said the Huawei network would transmit voice and data "to serve a range of potential railway uses".

These included "data capability for personal security", "bodyworn cameras", "live CCTV images sent back to a central monitoring room of security staff in dangerous place" and "geolocation – tracking of personnel and assets".

The document, which was released to the WA Opposition under freedom of information laws, also revealed "the timely and successful implementation of the new digital system is a precursor for the planned ATC [Automatic Train Control] project and Metronet extensions".

Opposition integrity and procurement spokesman Tjorn Sibma accused the government of deliberately covering up the sensitivity of the project.

"The Premier tried to distance himself from the Huawei Metronet project by not taking this important matter to Cabinet despite long-standing Cabinet protocols, the project value exceeding $200 million and his own department engaging Commonwealth intelligence agencies due to national security concerns," he said.

"Premier McGowan and Minister Saffioti then tried to downplay the importance of the project by characterising it as a simple telephone system for train drivers.

"However, when confronted with documents released under the Freedom of Information Act it became clear that this project had significant long-term implications for Western Australia, including for the imminent $1 billion automatic train control system."

A state government spokesman said "the initial focus of the [Huawei] Radio System Replacement project is only to support voice communications".

"The briefing note, which was prepared five months before the contract was awarded, makes clear that the network could 'potentially' support those uses some time in the future," he said.

"The use of the radio network for these purposes is not part of the current project scope.

"There is no current proposal before government to use the system for cameras or geolocation tracking. Any future uses of the system would be subject to ongoing security assessment."